An image display apparatuses to be mounted on a head of a human is known which forms an image on the retina of an eye by projecting light directly onto the retina (e.g., Patent Documents 1 and 2, and Non-Patent Document 1). For example, such an image display apparatus is referred to as a head mount display (HMD).
There are two projection techniques employed in HMDs are known: the scanning and the non-scanning projections. In the scanning projection, a laser light ray corresponding to a single pixel scans a plurality of positions corresponding to respective pixels in an image, thereby forming that image on the retina. For the scanning, for example, micro electro mechanical systems (MEMS), such as micro mirrors, are used. In the non-scanning projection, an image is formed on the retina by generating a plurality of light rays that correspond to respective pixels in the image and are arranged in a grid on a plane.
Furthermore, detection apparatuses are known which illuminate light on the retina of an eye of a subject and detect the intensity of light reflecting off the retina (e.g., Patent Documents 3 and 4, and Non-Patent Document 1).
For example, the HMD disclosed in Non-Patent Document 1 forms an image on the retina by means of the scanning projection. Furthermore, the HMD detects the intensity of reflection light from the retina.
Patent Document 1: Japanese Laid-open Patent Publication No. 2015-15563
Patent Document 2: Japanese Laid-open Patent Publication No. 2014-222289
Patent Document 3: Japanese Laid-open Patent Publication No. 2014-209980
Patent Document 4: Japanese Laid-open Patent Publication No. 2015-33423
Non-Patent Document 1: Kuriyama and two others, “Wearable display with personal authentication”, Proceedings of The 31st Sensor Symposium on Sensors, Micromachines and Applied Systems, IEEJ Sensors and Micromachines Society[Ed], Institute of Electrical Engineers of Japan, Oct. 20, 2014, 21pm3-PS68